Electric circuit breaker with compressed fluid blowout



Oct. 5, 1943.

B. M. H: P. FERNIER ELECTRIC CIRcUlT BREAKER lwml COMFRESSE'D FLUID BLowouT l Filed 4.my 29, 1939 Engl.

2y sheets-sheet 1 MMM Oct. 5,1943; B. M. H. P. FERMER 42,330,820

ELECTRIC CIRCUIT BREAKER WITH COMPRESSED FLUID BLOW OUT Filed' July 29.'1939 2 sheets-sheet 2 .[3/ /2 '//1 C 'lllVIIIIlllIl/IlllllllllllllllIlIlllll Patented Oct. 5, 1943 ELECTRICCIRCUIT BREAKER. WITH COM- PRESSED FLUID BLOWOUT Bernard Marie HilairePaul Fernier, Lyon,

France; vested in the Alien Property Custodian Application July 29,1939, Serial No. 287,348 In Germany July 30, 1938 Claims.

This invention relates to electric circuitbreakers and more particularlyto those which themselves supply the energy required for blowing thearc.

Circuit-breakers which themselves supply the energy required for blowingthe arc generally comprise means for storing up potential energy duringthe operation of closing the contacts and then deliver said energy onseparation of the contacts to impart to the fluid for blowing the arc acertain degree of pressure. Compressed air is generally used to blow thearc. The potential energy referred to is predetermined for a given typeof apparatus. When the intensities of the short circuit currents to bebroken exceed a certain value, the type of circuit-breaker referred tocan no longer be used, as it then becomes necessary to supplysupplementary energy from a source outside or apart from thecircuitbreaker.

One of the objects of the present invention is to provide an electriccircuit-breaker with compressed fluid blow out and which supplies itsown energy for blowing the arc, in which the rupturing power isincreased. With this object in view the circuit-breaker in accordancewith the invention contemplates the production by said circuitbreaker ofa supplementary quantity of energy over and above a given intensity ofcurrent which passes through the arc at break, said supplementaryquantity of energy being supplied from a different source from thelatter for effecting the blow out.

In accordance with the invention the two quantities of energy referredto may act simultaneously or else said supplementary energy acts firstand produces a preponderating blast, the blast produced by the otherquantity of energy not beginning to act until some time after saidformer quantity.

The invention has other aims and objects in addition to those above setforth, all of which will be readily understood from the followingdescription taken in connection with the accompanying drawings ofembodiments of the invention herein given for illustrative purposes, thetrue scope of the invention being more particularly pointed out in theappended claims.

Fig. 1 shows an illustrative embodiment of the invention;

Fig. 2 is a longitudinal section of that part of the circuit-breakercontaining the fixed contact and the two auxiliary contacts, andillustrates, upon a larger scale, the means for obtaining a concentricow of the air currents;

Fig. 3 illustrates certain modications of the apparatus shown in Fig. 1;

Fig. 4 shows further modifications;

Figs. 5, 6, 7 show the cam 3 in three principal positions.

Referring to Fig. l there is therein represented partly in elevation andsection and partly in per spective a circuit-breaker of the general typedescribed comprising an air compressor having a piston operated by a.spring and tensioned before the closing of the contacts of saidcircuit-breaker, said spring being capable of Storing up in advance theenergy required for the closing and separating of said contacts as wellas the energy required to produce the compressed air required forblowing the arc.

In said figure the compressor piston l is connected on the one hand tothe free end of a powerful spring 2 and on the other hand to a cam 3which is operated by mechanism herein shown in perspective for the sakeof elearness. A shaft 4 of this mechanism is directed perpendicularly tothe plane of said figure and its projection is shown at 4 whichdesignates the axis of oscillation of the cam, which is moved by saidmechanism in a contra-clockwise direction. In the course of this rotarx7movement it can engage and` carry with it a roller 5 upon one arm of abell crank lever 6 which controls the main movable contact 1 of thecircuit-breaker, the fixed contact of which is indicated by 8. These twocontacts draw an are herein called the principal arc and designated by9. Said circuit-breaker is further provided with an auxiliary fixedcontact lll and an auxiliary movable contact Il which, when theintensity of the current to be broken exceeds a given value, draw an archerein called the auxiliary are and designated by I2 and which is struckin series with the main arc (or principal arc).

In this figure the circuit-breaker is shown with its arc drawingcontacts separated, the action of the cam 3 on the movable contact Ithen being as follows. Said cam has a iull portion 3a and a cam groove3b. When said cam engages said roller 5 said full portion 3a causes thelever 6 to swing clockwise about its fulcrum thus closing said principalcontacts 1 and 8. With the circuitbreaker being thus in circuit closingposition, said roller 5 is opposite the entrance of said cam groove 3b.The separation of said two principal contacts takes place by a furtherrotation of said cam 3 in the course of which said roller 5 leaves saidcam groove 3b. The details of this operation will appear more fullybelow. The auxiliary movable contact li is operated by a bell cranklever i3 against the action of a spring I4 which tends to keep theauxiliary contacts IB and II separated. These two cont-acts are kept inclosed position by a heil crank lever l5, one arm of which is oppositethe movable core of an electric relay I6 which is energized by the maincurrent passing through the circuit-breaker.

The tensioning of spring 2 to store up energy to closeI and then toseparate the contacts or the circuit-breaker and to blow the" principalarc, is4

effected as follows:

Rotation of the shaft i on whichis splined the cam 3 is eiiected by acrank I'lfwhich by means of an endless screw device i3 ofwhich the wheelis loose upon said shaft, and a lever I9 actua-tes a driving member 2Bcarried bysaid shaft. When in its contra-clockwise rotation said cambrings its end 3a opposite said roller 5, said spring 2 will betensioned and a pawl 2l engages a bell crank lever 22 ofv which one armis opposite'the movable core of a winding' 23 adapted to venect closingmovement of the contacts ofthe circuitbreaker'. Furthermore, bythetensioning movement of said spring 2 an inclined plane 24 is moved toact upon a roller 25v carried-by a bell crank lever 25 and thus througha suitable connection swinging said bell crank lever I3 contraclockwiseabout a iulcrum to close the auxiliary contacts I0, II, said lever I3engaging said bell crank lever I5.

Closing movement of the principal contacts 'i and 3 of thecircuit-breaker is effected by sending an energizing current through thewinding 23 which causes the movable core of the latter to swing the bellcrank lever 22 about its fulcrum thus freeing the pawl 2i. Said'shaft 4lis thus unlocked, and under the' action of said spring 2, said cam 2isv rotated counter clockwise and rotatesl said shaft il. vDuring thistime the part 3a of said cam Sfcauses bell crank lever 6 to swingclockwise about its fulcrum to close the principal contacts l and il;When saidy contacts are thus closed, pawl 2l engages bell vcrank lever2l, one arm of which is opposite themovable core of a winding or coil 2tadapted to effect the separation of said principal Contact.

To effect an ordinary separation of said contacto an energizing currentissent through said coil 22. The resulting movement of its coil rotatessaid lever 2l and disengagessaid pawl 2 i. Shaft el` being thusunlocked, cam 3 is caused t'o rotate contra-clockwise by spring 2 which`was only partially distendedv during the closing movement of saidprincipal contacts. However the principal movable Contact does notimmediately start its movement as the roller' 5 passes along the cam`groove 3b from which it is not yet freed. During this time the air'atthe left of. piston I is pushed back through a hollow insulator 29 whichsupport'sa part oi the circuit-breaker and into a chamber 3d in which islocated the principal nxed contact '8; so as not to effect theseparation of said two principal contacts until the air pressure iorblowing the arc has reached its most efficient value. As the roller.leaves said cam groove 3b thus liberating said lever 6` the latterswings contra-clockwise under the action of 'spring' 3i, and thusseparates said principal contacts l and t. and the principal arc 9 isblown by the compressed' air which continues to blow through saidchamber 30, driven by the pist'on'l which reachesl the endv ci itsstroke under the action oi spring f2. v

In accordance with the invention supplementary energy for the blast isborrowed from the auxiliary arc. To this end contacts Iii and II arelocated within a chamber 3i preferably separated from the chamber 3Bcontaining the principal fixed contact as above set forth. The gasesgenerated by said auxiliary arc i2 as well as the air within saidchamber 3l the pressure of which is increased to a very high degree bythe heat generated by said auxiliary arc, are blown against theprincipal arc 9, either directly or after contacting with a name shield32 by which they are cooled, the blast thus furnished being of anintensity proportionate to the intensity of the current to beinterrupted.

In accordance with the invention also said auxiliary arc I2 forms beforethe principal arc when the intensity of the current to be interruptedexceeds a certain intensity value. To this Yend means are providedherein comprising a relay i6 which operates instantaneously but cnlywhen said intensity value is exceeded, the coil 28 for separating thecontacts being supplied with current by a relay 33 the operation or"which is retarded.

When the intensity of the overcharge current to be interrupted isinferior to said intensity value above referred to, the relay 33 aloneoperates and said coil 2S causes separation of the arc drawing contactas above setl forth. On the other hand when the intensity of the currentto be interrupted exceeds said intensity value, said relay I5 operatesimmediately to free said lever I3 which under Ythe action of said springle separates said auxiliary contacts. Furthermore said lever i3 inturning about its iulcrum acts upon'the lever 25 to cause the latteralso to turn and move the core of` said coil 28 through a suitable linkconnection 3e. The lever` 2l is thus freed and the principal contacts 1,8 start to separate but only when said roller 5 has escaped from saidcam groove 3b, that is to say after a certain time has elapsed and afterseparation of contacts It) and il.

To the blast produced by said auxiliary arc I2 there is therefore addedthat produced by piston i. To facilitate this the currents oi compressedair produced by said arc I2 and said piston are directed against the arc9 along parallel courses. As shown in Fig. l, said two air currents areconcentric.

SaidV two compressed air currents act simultaneously and thus combinetheir blowing action. The blast from piston i continues after extinctionof the arcs S and I2., thus scouring the space between and about theprincipal contacts l and 8 and precluding any restriking of the arc.

The invention contemplates the use of any suitable arrangement toproduce the concentric flow of said two compressed air currents. In theillustrative embodiment of the invention this result may be obtained byusing a principal iixed contact which is hollow and the hollow interiorof which communicates with the compressor cylinder as shown in Fig. 2.This gure is a longitudinal section of that part of the circuitbreakercontaining the principal xed Contact the two auxiliary contacts theremainder of said circuit-breaker having the same arrangement as thatshown in Fig. 1. Referring to'Fig. l a channel 35 leads from aninsulator 29 and conducts the air propelled by piston I into theinterior space 36 of said mainixed contact 8.

The interior chamber of the hollow xed principal contact may communicatewith the chamber in which the auxiliary arc is formed. Such anarrangement is shown in Fig. 3. As in the `case of Fig. 2 so also in thecase of Fig. 3, only that part of the circuit-breaker containing theprincipal fixed Contact and said auxiliary contact is illustrated, theremainder of said circuitbreaker being of the same construction as thatshown in Fig. l. The principal and auxiliary contacts as well as thearcs struck thereby are indicated in said Figs. 2 and 3 by the samereference characters as in Fig. 1. In Fig. 3, the interior chamber ofthe hollow fixed contact 8 communicates with the chamber 3| in which theauxiliary arc is struck and the concentric chamber 38 of said hollowcontact communicates with the air `compressor which is diagrammaticallyindica-ted by said piston 39.

In accordance with the invention a certain degree of simultaneous actionof the two compressed air currents referred to may be obtained bydirecting said currents in opposite directions against said arc 9 'asshown illustratively in Fig. 4. In

vthe illustrative embodiment shown in said ligure the operation of themain and auxiliary contacts and the generation of the air blast may beand, as is herein shown, are identical with those illustrated in Fig. 1.The corresponding means have been omitted from Fig. 4 in order notunnecessarily to complicate the drawings, only the piston I, the drivingspring 2, the lever 5 for ,operating the principal movable contact 1,that part of the circuit-breaker containing the principal xed contact 8and the auxiliary contacts, as well as the particular means .andfeatures to be considered have been shown diagrammatically in order thatthe invention may be clearly understood. The compressed air heated bythe auxiliary arc is conducted to the fixed contact 8, while the airdriven by the piston I is conducted through said hollow insulator Z9into a cylinder 40 in which said movable contact 'I operates. The gasesand the compressed air produced by the arc I2 are directed against thatpoint of attachment of the arc 9 which is within the chamber 4I whilethe blast of compressed air from the piston I is conducted throughopenings or ports provided in a partition 42 and into a pipe 43surrounding the movable contact, whence it directed against the otherpoint of attachment of said arc 9.

The energy for the blast generated by said auxiliary arc and thatproduced by the compressor may act successively. In that case the blastgenerated by said auxiliary arc, which always preponderates, starts rstand operates alone. The blast from the compressor starts to operatelater and adds its operation to that generated by said arc; it scoursthe space separating and surrounding the contacts 'and completes theblowing of the arc, thus precluding any restriking of the latter. Anyone of the farms of circuit-breakers above described. may be providedwith a resistance serving to delay the re-establishment of the tension.Said resistance may be applied either mechanically or pneumatically andwill preferably shunt the 'auxiliary arc and, the case arising, theprincipal arc. When the intensity of the current (short circuit) t0 becut is weak, the interruption of said current is effected without theinsertion of said resistance by using only the blast produced by thecompressor. When however said intensity becomes considerable the arc ofthe auxiliary contacts produces a blast and inserts or throws saidresistance 8l into operation. The current which remains for theprincipal contact to cut is therefore only a current the intensity ofwhich has been reduced by said resistance.

A capacity may be substituted for said resistance in all thecircuit-breakers of the latter type and said capacity may be renderedoperative either mechanically or pneumatically and will preferably shuntthe auxiliary arc and the case arising the principal arc.

The compressed air blast produced by the compressor cylinder may notonly act simultaneously with that supplied from the chamber in which theauxiliary arc is struck but may also act after the arc has beenextinguished. This has the advantage that the space about the contactsis efficiently and thoroughly scoured, any restriking of the arc beingthus precluded. This operation takes place automatically in the majorityof the apparatus above described, by causing the principal contacts andthe auxiliary contacts to move at a suitable regulated speed and bymaking the compressor plant of suitable dimensions.

Among the many advantages possessed by apparatus embodying the presentinvention may be mentioned the increase in the rupturing power of theusual circuit breakers which themselves compress the air required forblowing their arcs, as well as the possibility of regulating theintensity of the arc-extinguishing blast proportionally to the intensityof the current to be cut, and the fact that small arcs can beextinguished as well as larger arcs.

I am aware that the present invention may be embodied in other` specicforms Without departing from the spirit or essential attributes thereof,and I therefore desire the present embodiments to be considered in allrespects as illustrative and not restrictive, reference being had to theappended claims rather than to the foregoing description to indicate thescope of the invention.

I claim:

l. Electric circuit breaker with compressed fluid blow out, comprising,in combination, relatively movable main arc-drawing contacts; relativelymovable auxiliary arc-drawing contacts mounted in series with said mainarc-drawing contacts; a chamber for said main arc-drawing contacts; aseparate chamber for said auxiliary aro-drawing contacts; mechanism foropening and for closing said main arc-drawing contacts; mechanism foropening and for closing said auxiliary arc-drawing contacts; fluidcompressing mechanism operatively connected tothe arc-drawing contactclosing mechanism; means for rendering said auxiliary arc-drawingContact opening mechanism operative to open said contacts only when andafter the current to be cut reaches a certain intensity, and before themain contacts are opened; means to direct a blast of compressed fluidagainst the main arc from said fluid compressing mechanism; and means todirect a blast of compressed iluid against said main arc 'from thechamber of said auxiliary arc.

2. Electric circuit breaker with compressed fluid blow out, comprising,in combination, relatively movable main arc-drawing contacts; relativelymovable auxiliary arc-drawing contacts mounted in series with said mainarc-drawing contacts; a chamber for said main arc-drawing contacts; aseparate chamber for said auxiliary arc-drawing contacts; mechanism foropening and for closing said main arc-drawing contacts; mechanism foropening and for closing said auxiliary arc-drawing contacts; fluidcompressing mechanism, including a piston operatively connected to thearc-drawing contact closing mechanism;

:means`V for rendering said 'auxiliary arc-drawing contact openingmechanism operative to open said auxiliary contacts only when and afterthe current to be cut reaches a certain intensity, and before the maincontacts are opened; rneans to direct a blast of compressed fluidlagainst the main arc from said duid 'compressing mechanism; and meansto direct a blast of compressed iiuid against said main arc from thechamber of said auxiliary arc.

3. Electricv circuit breaker with compressed iiuid blow out, comprising,in combination, a fixed main arc-drawing Contact; a chamber containingsaid Contact; an inclosure for said chamber, terminating in an exhaustmouth-piece for the compressed duid blast; a movable main arcdraWingcontact adapted to be Withdrawn out- Wardly from said chamber and saidinclosure to draw an are; relatively movable auxiliary arcdrawingcontacts mounted in series with said main arc-drawing contacts in asecond chamber near that containing said fixed main arc-drawing contact;mechanism for opening and for closingsaid main arc-drawing contacts;mechanism for opening and for closing said auxiliary arc-drawingcontacts; a cylinder provided with a piston to provide compressed fluidWithin the circuit breaker, said piston being operatively connected tosaid arc-drawing contact closing mechanism; means for rendering saidauxiliary arcdrawing contact opening mechanism operative `to open saidauxiliary contacts only when and after the current to be cut reaches acertain intensity, and before the main contacts are opened; means forconveying compressed uid from said cylinder into said chamber containingsaid fixed main arc-drawing contact; and means for conveying-compressedfluid from said chamber containing said auxiliary arc-drawing contactsbetween said chamber containing said nxed main contact and said exhaust'mouth-piece.

' 4. Electric circuit breaker With compressed fluid blow out,comprising, in combination, a iixed main arc-drawing contact; a chamberadapted to contain said contact and terminating in an exhaustmouth-piece for the compressed uid blast; -a movable main arc-drawingcontact adapted to be withdrawn outwardly from said mouth-piece; a tubemounted opposite said mouth-piece and in alignment therewith to receivesaid movable contact when it is Withdrawn I from said mouth-piece;relatively movable auxiliary arc-drawing contacts mounted in series withsaid main arc-drawing contacts, in a cham, bei` near that containingsaid fixed main arcdrawing contact; mechanism for opening and forclosing said main arc-drawing contacts; mechanism for closing saidauxiliary arc-drawing contacts; a cylinder containing a piston tofurnish compressed duid in the circuit breaker, said piston beingoperatively connected to the arc-drawing contact closing mechanism;means adapted to open said auxiliary arc-drawing contacts only when andafter the current to be cut reaches a certain intensity and before themain contacts are opened; means to convey the fluid compressed by saidauxiliary arc into said mouthpiece, and means to convey fluid compressedby said cylinder into said tube, the main arc thus receiving a blast ofcompressed fluid from said mouth-piece and a blast of compressed uuidfrom said tube.

5, Electric circuit breaker with compressed fluid blow out, comprising,in combination, relatively movable main arc-drawing contacts; a chambercontaining said contacts; auxiliary arcdrawing contacts mounted in achamber separate from that containing said main arc-drawing contacts andin series With the latter; mechanism for closing said main arc-drawingcontacts and said auxiliary arc-drawing contacts, the mechanism forclosing said main arc-drawing contacts including a cam for closing thelatter; mechanism for opening said main arc-drawing contacts and foropening said auxiliary arc-drawing contacts; a cylinder and piston toprovide compressed duid in the circuit breaker, said piston beingoperatively connected to the arc-drawing contact closing mechanism, thepiston rod being connected to the mechanism for closing said auxiliaryarc-drawing contacts; an electric relay to render said auxiliaryarc-drawing contact opening mechanism operative to open said aiuriliarycontacts only when and after the current to be cut reaches a certainintensity and before said main arc-drawing contacts are opened; means todirect a blast of compressed fluid against the main arc from saidcylinder; and means to direct a blast of compressed fluid against themain arc from said chamber of said auxiliary arc.

BERNARD MARIE HILAIRE PAUL FERNIER.

